Oil soluble photoprotective compounds and compositions from plant oil processing

ABSTRACT

Co-product streams derived from the manufacture of vegetable oil were further processed producing materials that possess strong absorbance of visible and ultraviolet light. The compounds contributing to the light absorbance were increased and standardized to produce a fat-soluble composition with consistent and strong absorbance of ultraviolet and visible light. The fat-soluble composition is a useful photoprotective agent for various applications including protection of herbicides and pesticides. In a preferred embodiment acidulated vegetable oil is blended to a constant absorbance of light between 190 and 400 nm and used in a formula to protect a field-applied herbicide.

CROSS REFERENCE TO RELATED APPLICATIONS

This application contains disclosure from and claims the benefit underTitle 35 United States Code § 119(e) of U.S. Provisional ApplicationSer. No. 60/367,585, filed Mar. 26, 2002 and entitled “Oil SolublePhotoprotective Compounds and Compositions from Plant Oil Processing”.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO MICROFICHE APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of photoprotective compounds,and more particularly to photoprotective compounds from plant oilprocessing.

2. Background Art

Pesticides, herbicides, xenobiotics and other useful chemicals arecommonly applied to fields, forests, roadsides and other locations wherethey may be degraded by exposure to light. Similarly, living organismsincluding bacteria, bacterial spores, fungi, fungal spores, viruses andviral spores are increasingly being applied in the environment for theirbeneficial effects. Exposure of these materials and beneficial organismsto light often decreases their effectiveness by altering their chemicalstructures or diminishing their biological activity. Photoprotectivestrategies can be employed to maintain or increase the effectiveness ofthese compounds and organisms.

Wood, plastic, fabric and many other construction materials are alsodegraded by visible and ultraviolet light. Over time exposure to lightwill fade or discolour such materials and decrease their integrity.Photoprotective strategies may also be employed to maintain theintegrity and appearance of these materials.

Virus particles may be mixed with opaque solids such as carbon black tomaintain viability by protection from white light in the method of U.S.Pat. No. 3,541,203. U.S. Pat. No. 5,939,089 teaches methods of coatingviral spores with kraft lignin. The coated virus spores possess enhancedresistance to ultraviolet light.

Insecticide compositions containing pyrethinoids are highly susceptibleto light degradation. According to U.S. Pat. No. 3,264,176 insecticidepowders may be stabilised against light degradation by absorption ontocharcoal. The disadvantage of this method is the tendency of darkmaterials to heat in the environment. Heat as well as light exacerbatesthe processes involved in degradation and inactivation. Reflectivepigments including titanium dioxide can be used in place of carbon blackaccording to U.S. Pat. No. 2,168,064 but the added cost of thesematerials limits their application. Dextrins and gums also provideprotection to pyrethinoids. (U.S. Pat. No. 3,130,121). Strong UVabsorbing compounds may be mixed with pyrethinoids to maintain activity.Diisophorone, for example, may be mixed with pyrethinoids to protectthem from light wavelengths between 210 and 350 nm according to U.S.Pat. No. 3,839,561. Pyrethinoids may also be stabilized by the additionof amyl-paradimethylamino benzoate and a suitable antioxidant (U.S. Pat.No. 3,560,613).

Endosulfan and chlorpyriphos are also noted to be unstable to lightexposure. U.S. Pat. No. 5,549,903 teaches of the use of ureaencapsulation and light absorbing compounds to produce a stabilizedinsecticide product.

Petroleum spray oils may be used to control a number of fungi andinsects (U.S. Pat. No. 3,098,000) but these oils are subject to harmfuloxidation catalyzed by ultraviolet light. Degradation of the oils causesthem to become phytotoxic.

Combinations of anti-oxidants and light absorbents may be added to theoils to prevent degradation and phytoxicity.

Synthetic light absorbing compounds may be highly effective but they areproduced from non-renewable resources and they may have undesirable sideeffects. For example, U.S. Pat. No. 2,772,198 demonstrates that4-amino-azo-benzene provides excellent protection of pyrethinoids butthis compound is a potent carcinogen. Acidulated soybean and otheracidulated vegetable oils are commonly used as adjuvants for herbicidalcompounds. Gednalske reported that blends of a non-ionic surfactant andacidulated soapstock were effective in preparing a carrier solution forthe application of herbicides (U.S. Pat. No. 5,260,260). U.S. Pat. No.5,521,144 teaches that mixed tocopherols may be added to acidulatedsoapstock to improve the environmental stability of active ingredientsapplied with the adjuvant. Acidulated soapstock may also be used inherbicidal compositions to decrease odours as taught by Gednalske andHerzfeld (U.S. Pat. Nos. 5,463,180 and 5,719,102).

Soapstock is a co-product obtained in the manufacture of vegetable oil.It is commonly used in wide-ranging applications including animal feedand road dust control. Industrial soapstock is a highly variableproduct, which contains significant amounts of pigments, colour bodiesand other compounds. Acidulated soapstock is prepared by adding acid tosoapstock and recovering oil from the acidified solution. The acidulatedoil solution is a concentrated source of plant pigments.

BRIEF SUMMARY OF THE INVENTION

The instant invention discloses the surprising discovery that acidulatedsoapstock may be prepared to maximize and standardize the content oflight absorbing compounds. When appropriately processed the soapstockhas sufficient light absorbance to be used as a photoprotective adjuvantfor pesticides, herbicides, xenobiotics, other useful chemicals,bacteria, bacterial spores, fungi, fungal spores, viruses and viralspores.

The present invention teaches methods of preparing soapstock to enhanceand standardize the light absorbance characteristics. Furthermore, italso teaches the application of acidulated oils as naturalphotoprotective agents. Acidulated oils with strong light absorbancebetween 190 and 700 nm wavelength may be used to protect environmentallyapplied pesticides, herbicides, xenobiotics, other useful chemicals,bacteria, bacterial spores, fungi, fungal spores, viruses and viralspores. Similarly acidulated oils may be able to maintain wood,plastics, fabrics and construction materials that are exposed to visibleand ultraviolet light.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and other attributes of the invention will become more clear upona thorough study of the following description of the best mode forcarrying out the invention, particularly when reviewed in conjunctionwith the drawings, wherein:

FIG. 1 is a graph illustrating the spectrum of acidulated soapstockdiluted to a concentration of 1.0% with n-hexane.

DETAILED DESCRIPTION OF THE INVENTION

The present invention includes methods of preparing acidulated oils withstrong light absorbing characteristics. The light absorbance is due tothe presence of specific compounds that may be preferentiallyconcentrated during soapstock preparation or during acidulation. Thelight absorbing oil soluble compounds include but are not limited tonaturally occurring oil soluble protein, tocopherol, phaeophytin,carotenoid, quinone, quinol, phenolic, and ferulate ester. The lightabsorbing oil also includes chemically modified compounds where themodification is controlled by extraction and acidulation conditions.

The invention also teaches that although all acidulated soapstock hassome light absorbance the absorbance characteristics are too variablefor the reliable production of a useful light adsorbing oil. The lightadsorbing quality of the oil is subject to wide ranging factors.Compounds present in the acidulated oil vary considerably depending onthe species and genetic factors. The utilisation of soapstock from theprocessing of soy, canola, rapeseed, palm, sunflower, peanut,cottonseed, flax, rice bran is included in the current invention. In apreferred embodiment acidulated soapstock derived from the manufactureof soybean oil is utilized for its photoprotective effects. In anotherpreferred embodiment acidulated soapstock are blended to minimisedifferences in light absorbance and to produce a consistent product.

Furthermore, conditions used in oil extraction by different commercialoperations greatly affect the light absorbance properties of thesoapstock. For example, in one industrial process soapstock is preparedsuch that it includes phospholipids and glycolipids as a major componentwhile other soapstock has only minor amounts of these compounds.Phospholipids significantly affect the light absorbance of theacidulated oil. The current invention includes but is not restricted toacidulated oils that are produced from soapstock materials that includephospholipids and glycolipids.

Oil extrusion, tempering conditions, expeller pressing and solventextraction methods vary between manufacturers of vegetable oil. Theseprocessing methods alter the light absorbance characteristics of thesoapstock. It is also part of the current invention to utilizeextraction protocols such as modified extrusion methods, expellerpressing and solvent extraction to enhance the light absorbance of theacidulated oil. In a preferred embodiment of the current invention thesoapstock is derived from expeller pressed oils. In another embodimentthe soapstock is derived from solvent extracted oils. The soapstock mayalso be recovered from mixtures of solvent extracted oils and expellerpressed oils.

Conditions employed during acidulation also affect the absorbance of theoil. For example, the temperature of acidulation, the type of acid usedfor acidulation and duration of the acidulation treatment significantlyaffect oil light absorbance properties. The current invention includesconditions that occur during acidulation that enhance or alter oilabsorbance properties. In a preferred embodiment the acidulation occursat a pH of less than 2.0. In another preferred embodiment theacidulation occurs at a pH of 1.5 and a temperature of 90-110 C. Inanother preferred embodiment sulfuric acid is used to acidulate the oil.It is known to those skilled in the art that any of a number of mineraland organic acids may be used for acidulation. Due to the price of theacid used it may be preferred to utilize sulfuric acid.

Normally the major components of acidulated oils are fatty acids,partial glycerides and triglycerides. The fatty acids and glyceridesthemselves have only limited light absorbance characteristics, with astrong absorbance due to their carbonyl functionality at wavelengthsless than 210 nm. Therefore, the glycerides act to dilute the lightabsorbing compounds. Selectively removing fatty acids and glycerides canconcentrate the light absorbance of the oil producing intenselyabsorptive oil. In particular, it is possible to selectively removefatty and mono glycerides from acidulated oils by distillation. It is anembodiment of this invention where fatty acids and glycerides areremoved from acid oil to increase the concentration of light absorbance.In a preferred embodiment fatty acids are removed from the acid oil bydistillation. In another preferred embodiment fatty acids are removedfrom the acid oil by short path distillation.

The light absorbance characteristics of acidulated oils are not equal atall wavelengths. It is possible to augment the light absorbancecharacteristics by the addition of oil soluble pigments. Pigments fromnaturally occurring sources are preferred but the use of syntheticpigments is an embodiment of the current invention.

The photoprotective acidulated fatty acids may be used in anyapplication for protection of light exposed materials. In a preferredembodiment the photoprotective action is utilised in herbicide spraymixtures to maintain the biological activity of the herbicide. Inanother preferred embodiment the photoprotective action is used tostabilise wood against chemical attack.

EXAMPLES Example 1 Laboratory Preparation of Acidulated Canola Oil andits Light Absorbance Characteristics

Canola soapstock was obtained from a commercial manufacturer ofvegetable oil. Four hundred grams of the soapstock were blended with 24grams of sulfuric acid in a 4-liter glass beaker using a stainless steelspatula. The mixture was heated 95 C then held at that temperature for15 minutes on a hot plate equipped with a teflon coated magnetic stirrerbar. After acidulation the contents of the beaker were cooled. Thebeaker contents were transferred to a separatory funnel where, aftersettling, the lower water layer was removed (221 g—water). Anintermediate layer of viscous material was then taken from the funnel(12 g—emulsion) followed by an upper layer of black coloured oil (181g—of acidulated soapstock). The extracted oil was dissolved to aconcentration of 10%, 1.0%, 0.1% and 0.01 w/w in spectrophotometry graden-hexane.

Visible and ultraviolet light spectra of all dilutions of acidulatedsoapstock were measured using a dual beam UV/visible spectrophotometer.The spectrum of the 1.0% dilution is shown in FIG. 1.

Example 2 Commercial Scale Acidulation of Soy Oil

Soybean soapstock was obtained from a commercial manufacturer ofvegetable oil. Four thousand pounds of sulfuric acid was added to eightythousand pounds of soapstock with continuous agitation in a fiberglassresin reactor tank. The temperature of the mixture was increased to 95 Cby injection of steam while maintaining continuous agitation. Afteraddition of acid and heat treatment the mixture was subject to 2additional hours of agitation at 95 C the contents of the reactor tankwere transferred to a settling tank. After 24 hours 35,000 pounds ofacidulated oil were removed from the top of the tank. The oil possessedstrong UV absorbance characteristics.

Example 3 Greenhouse Performance of Grass Herbicides as Influenced byAdjuvants Including Using an Acidulated Oil as an Adjuvant

Spray mixtures of the herbicides (+/−)2-{(E)-1-{3-chloroallyloxyimino]propyl]-5-{2-(ethylthio)propyl}-hydroxycyclohexen-2-one(Select) and2-{1-(ethoxyimino)butyl}-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one(Poast) were prepared with an non-ionic surfactant adjuvant includingacidulated soybean oil and without the acidulated oil. The non-ionicsurfactants were added to a water spray solution at a concentration of0.25% v/v ai and applied to yellow foxtail plants in the greenhouse. Theapplication rate of Select and Poast was 2 fl. and 6 fl. Oz/Acre,respectively. Control of grassy weeds was assessed as reduction in dryweight of the plants compared to untreated control plants 27 days afterapplication. Control data was statistically analyzed using analysis ofvariance methods. Differences between means reported in the Table I weredetermined at p=0.05 using the Student-Newman-Keuls method.

TABLE I Barnyard grass Yellow Foxtail Field Sandbur Percent PercentPercent control* control* control* 27 days after 27 days after 27 daysafter Treatment application application application Select (no adjuvant) 62 h 62 e 48 c Select (NIS)  94 b 72 d 67 b Select (NIS + acid. oil 100a 75 cd 75 a w/o strong UV absorbance) Select (NIS + acid. oil 100 a 78bc 77 a w strong UV absorbance) Poast (no adjuvant)  62 h 52 f 38 efPoast (NIS)  86 d 72 d 67 b Poast (NIS + acid. oil  90 c 82 b 72 a w/ostrong UV absorbance) Poast (NIS + acid. oil  96 b 87 a 73 a w strong UVabsorbance) *Percent reduction in dry weight compared to untreatedcontrol plants. ** Means followed by the same letter do notsignificantly differ (P = 0.05 Student-Neuman-Keuls)

Field Performance of a Grass Control Herbicide as Influenced byAdjuvants Including Using Acidulated Oil as an Adjuvant.

Spray mixtures of the herbicide (+/−)2-{(E)-1-{3-chloroallyloxyimino]propyl]-5-{2-(ethylthio)propyl}-hydroxycyclohexen-2-one(Select) was prepared with a non-ionic surfactant adjuvant includingacidulated soybean oil and without the acidulated oil. The nonionicsurfactants were used at a concentration of 0.25% v/v ai and applied tocorn and wheat plants in the field. The application rate was 2 fl.oz./Acre. Percent control of the corn and hard red spring wheat wasvisually assessed compared to untreated control plants 17 and 31 daysafter treatment. Control data was statistically analyzed using analysisof variance methods. Differences between means reported in the Table IIwere determined at p=0.05 using the Student-Newman-Keuls method.

Table II shows that when Select was applied without an adjuvant weedcontrol was poor. Inclusion of an adjuvant improved control of the cornwhile inclusion of a non-ionic surfactant with the acidulated oilincreased control even more.

TABLE II Corn Percent Corn Percent Wheat Percent Wheat Percent control*control* control* control* 17 days after 31 days after 17 days after 31days after Treatment application application application applicationSelect (no adjuvant)  10 c** 19 d 15 d 30 g Select (NIS) 123 c 40 c 34 d75 e Select (NIS + acid. oil w/o  19 c 47.5 c 31 d 80 de strong UVabsorbance) Select (NIS + acid. oil w  58 b 68 b 59 c 85 cd strong UVabsorbance) *Percent control assessed visually compared to untreatedcontrols. **Means followed by the same letter do not significantlydiffer (P = 0.05 Student-Neuman-Keuls)

Although only an exemplary embodiment of the invention has beendescribed in detail above, those skilled in the art will readilyappreciate that many modifications are possible without materiallydeparting from the novel teachings and advantages of this invention.Accordingly, all such modifications are intended to be included withinthe scope of this invention as defined in the following claims.

1. A method of producing a pesticide adjuvant, comprising the steps of:adding acid to a vegetable soapstock until a pH of about 2.0 isattained; maintaining temperature of acidulated vegetable soapstock in arange of about 90-110° C. during acidulation for a predeterminedprocessing time; and removing fatty acids, monoglycerides, andglycerides from the acidulated vegetable soapstock to concentrate thelight absorbance of the acidulated vegetable soapstock, wherein a 1 mmlayer of the acidulated vegetable soapstock absorbs greater than 99% ofimpingent UV-A and UV-B radiation.
 2. The method of claim 1 wherein thevegetable soapstock is selected from a group consisting of soybean,sunflower, palm, safflower, rice bran, rapeseed, flaxseed and oliveoils.
 3. The method of claim 1 wherein the acid is a mineral acid. 4.The method of claim 3 wherein the mineral acid is selected from a groupconsisting of sulphuric acid, hydrochloric acid, nitric acid andphosphoric acid.
 5. The method of claim 1 wherein the acid is an organicacid.
 6. The method of claim 5 wherein the organic acid is selected froma group consisting of citric acid, acetic acid, lactic acid, propionicacid, tartaric acid and carbonic acid.
 7. The method of claim 1 whereinthe pH is in the range of about 2.0 to 1.0.
 8. The method of claim 1wherein the temperature is maintained at about 95° C.
 9. The method ofclaim 1 wherein the predetermined processing time is about 2.0 hours.10. The method of claim 1 wherein the compounds are removed bydistillation.
 11. The method of claim 1 further including the step ofdiluting the acidulated vegetable soapstock to achieve a material thatabsorbs greater than 99.5% of impingent UV-A and UV-B radiation.
 12. Themethod of claim 11 wherein the acidulated vegetable soapstock is dilutedwith n-hexane.
 13. A method of protecting a material from lightdegradation by applying the acidulated vegetable soapstock produced bythe method of claim
 1. 14. The method of claim 13 wherein the materialprotected is selected from a group consisting of pesticides, herbicides,xenobiotics, bacteria, bacterial spores, fungi, fungal spores, viruses,viral spores, wood, plastics and fibers.
 15. The method of claim 14wherein the acidulated vegetable soapstock has a constant absorbance oflight between 190 and 400 nm, and wherein it is applied to afield-applied herbicide.
 16. The method of claim 15 wherein a 1 mm layerabsorbs greater than 99% of impingent UV-A radiation.
 17. The method ofclaim 15 wherein a 1 mm layer absorbs greater than 99% of impingent UV-Bradiation.